Have students gather five foam cups and number them with a marker before adding 100ml of distilled water to each one. Each student should wear latex gloves and cut an instant cold pack open. Measure out 10g of the ammonium nitrate crystals. Record the temperature of the water in the first foam cup. Add the ammonium nitrate and stir, checking the temperature every 30 seconds until it no longer decreases. Repeat the process with each cup, increasing the amount of ammonium nitrate added by 10g each time. Examine the results of the experiment and graph the temperature and time slopes. Calculate the difference in start and end temperatures, and determine the effect of increasing the amount of ammonium nitrate in the water.
Students of any age can build their own cold pack from household objects and examine the interaction between water and alcohol. Hypothesize whether water alone or water combined with alcohol creates a frozen solid faster. Combine 2 cups of rubbing alcohol and 6 cups of water in a gallon freezer bag. Fill another freezer bag with 6 cups of water only. Place the bags in your kitchen freezer and remove every 20 minutes to examine. Record data about the freezing process, including the amount of time it takes the water in each bag to freeze. Determine which bag is a better treatment for a minor injury and explain why.
Chemistry students can test a variety of chemicals to determine which are best for portable first aid during an in-class lab. Science teachers need to provide lab groups with ammonium chloride, sodium chloride and calcium chloride. Students should place 50ml of distilled water into three separate cups and record the temperature of each before adding a teaspoon of ammonium chloride to the first cup, sodium chloride to the second cup and calcium chloride to the third cup. Record the temperature of each cup every 30 seconds until each reaches stabilization. Compare the data collected and formulate conclusions based on the fastest-cooling sample and the sample that reaches the lowest final temperature.
Middle school students can test the effects of animal manure on instant cold packs in a fun, yet smelly experiment. Children need an instant cold pack, three gallon freezer bags and three different types of manure. Break the cold pack and insert a thermometer into the bag after 10 minutes to record the temperature. Place an amount of fertilizer equal to the weight of the instant cold pack in each gallon-size bag and add the same weight in water to each. Shake gently to mix. Record the temperature of each bag after 10 minutes. Compare data and conclude whether environmental cold packs are effective.